Metrology targets are designed to enable the measurement of parameters that indicate the quality of wafer production steps and quantify the correspondence between design and implementation of structures on the wafer. Metrology targets as specific structures optimize the requirements for device similarity and for optical measurability. Compliance of targets to semiconductor manufacturing design rules contributes to accurate production of the targets but may reduce the optical measurability of the targets.
U.S. Patent Application Publication No. 2012/0033215 and U.S. Pat. No. 8,243,273, which are incorporated herein by reference in their entirety, disclose adding dummyfill to a target design to improve compliance with design rules.